<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>

<body>
  <!-- 标签 h1-h6 -->
  <!-- 数字越小，里面的内容就越粗越大 -->
  <!-- 数字越大，里面的内容就越细越小 -->
  <h1>这是一级标题</h1>
  <h2>这是二级标题</h2>
  <h3>这是三级标题</h3>
  <h4>这是四级标题</h4>
  <h5>这是五级标题</h5>
  <h6>这是六级标题</h6>



</body>

</html>